共查询到20条相似文献,搜索用时 15 毫秒
1.
在电压0.6~1.0 MV,脉冲重复频率为100 Hz条件下,实验研究了爆炸发射阴极的有效发射面积、平均发射电流密度、二极管阻抗、电子束能量损耗机制等特性。结果表明:阴极有效发射面积随时间呈方波变化,在脉冲开始后5 ns内有效发射面积基本达到稳定。在碳纤维、天鹅绒、石墨、不锈钢4种阴极材料中,碳纤维阴极有效发射面积最大且变化相对稳定,并且碳纤维阴极具有最大的平均发射电流密度。二极管阻抗随着阴阳极间隙的增加并非呈平方关系增加,而是呈线性增长,阻抗失配是降低电子束能量传输效率的主要机制。 相似文献
2.
The energy and current balances in the diode unit of a high-current pulsed electron accelerator (350–500 keV, 60 ns, 250 J per pulse) are compared for an explosive emission cathode (made of graphite, copper, or carbon felt) and a multipoint (graphite or copper) cathode. The planar diode with the continuous cathode is shown to be more efficient in terms of conversion of the applied energy to electron energy (more than 90%) despite a delay in the plasma surface formation. With the impedance of the planar diode matched to the output resistance of the nanosecond generator, the efficiency of the diode does not depend on the time of plasma formation on the cathode. In the case of the graphite cathode, the plasma formation delay reduces the fraction of slow electrons in the forming electron beam and reduces electron losses in anode foil when the beam is extracted from the vacuum space of the diode chamber into the reactor. 相似文献
3.
V. N. Detinko 《Russian Physics Journal》1971,14(4):507-514
The capacitance of a planar diode is analyzed in the quasisteady-state approximation. The differential capacitance is derived for three operating modes of the diode: with a negative voltage on the anode, with a space-charge limited anode current, and at current saturation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 104–112, April, 1971. 相似文献
4.
S. Bollanti P. Di Lazzaro F. Flora G. Giordano T. Letardi D. Murra G. Schina C.E. Zheng 《Applied physics. B, Lasers and optics》1999,68(4):683-688
6 shots, the X-ray dose, uniformity, and ionisation rate values guarantee an effective preionisation of excimer laser discharges.
Owing to both the long lifetime and the substantial absence of maintenance, this X-ray diode seems suitable to preionise commercial
gas lasers, such as excimer and TEA CO2 lasers.
Received: 28 August 1998 / Revised version: 16 November 1998 / Published online: 24 February 1999 相似文献
5.
As a promising kind of high current cold cathode, the Ferroelectric Cathode (FEC) has several significant advantages, such as a controllable trigger time, lower vacuum requirement and large emitting area fabricability. The emitting current density of the FEC fabricated at Tsinghua University was more than 200 A/cm^2. In order to make the ferroelectric cathode into practical applications, a high current density diode using a ferroelectric cathode was designed, based on the PIC simulation. The performance of the FEC diode was investigated experimentally. When the applied diode voltage was 60 kV, a current density of more than 250 A/cm^2 was obtained, and the current density distribution was also measured. 相似文献
6.
As a promising kind of high current cold cathode,the Ferroelectric Cathode(FEC)has several significant advantages,such as a controllable trigger time,lower vacuum requirement and large emitting area fabricability.The emitting current density of the FEC fabricated at Tsinghua University was more than200 A/cm2.In order to make the ferroelectric cathode into practical applications,a high current density diode using a ferroelectric cathode was designed,based on the PIC simulation.The performance of the FEC diode was investigated experimentally.When the applied diode voltage was 60 kV,a current density of more than250 A/cm2 was obtained,and the current density distribution was also measured. 相似文献
7.
A. S. Chikhachev 《Technical Physics》2006,51(7):956-958
The electron dynamics in a planar gap with a variable accelerating potential across it is studied with a model solution to a self-consistent kinetic equation. 相似文献
8.
The dependence of the current on emitter size is obtained for a high-current planar diode with a discrete emitting surface.
It is shown that if the distance between the emitters appreciably exceeds their size, the dependence of the current on the
ratio of the emitter size to the diode gap is a power dependence with an exponent of 3/2. The voltage dependence of the current
obeys the “three-halves” law up to higher voltages than that for a planar diode with a homogeneous emitting surface.
Zh. Tekh. Fiz. 69, 97–101 (June 1999) 相似文献
9.
10.
11.
Yu. Ya. Volkolupov A. N. Dovbnya V. V. Zakutin M. A. Krasnogolovets N. G. Reshetnyak V. V. Mitrochenko V. P. Romas’ko G. I. Churyumov 《Technical Physics》2001,46(2):227-233
The effects of electric and magnetic field intensities, the triggering-pulse droop rate, and the electrode diameter on the processes of electron beam formation and generation were studied experimentally. The results of mathematical simulation of the secondary-emission multiplication of the electron flow are presented. Tubular electron beams with a wall thickness of 1.5–2 mm, a current density of 1–70 A/cm2, and a particle energy of 5–100 keV were obtained. It was shown that several electron bunches could be obtained during a single voltage pulse. 相似文献
12.
13.
The approximation of electron motion along electric field force lines is used to calculate current in diodes with knife-edge and point emitters. The diode current is limited by space charge, with each current tube considered as a diode element with electrodes in the form of coaxial cylinders or concentric spheres. The effect of the cathode cavity in which the emitter is installed upon current magnitude is considered by limiting beam dimensions at the anode.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 3–6, February, 1992. 相似文献
14.
E. Tomková 《Czechoslovak Journal of Physics》1972,22(5):356-363
The approximative theory taking into account the electron space charge, initial velocities of the electrons emitted with Maxwellian distribution and their elastic collisions with neutral gas particles has been applied to the gas filled planar diode. The presence of positive ions was not considered. As a result, the differential equation for the dimensionless potential has been obtained. Using its solutions the potential distribution and the current-voltage characteristics can be determined.Ke Karlovu 5, Praha 2, Czechoslovakia. 相似文献
15.
We have proposed a universal approximation of the normalized erosion zone profile of planar magnetrons with a disk cathode by a composite function that includes the probability density function for the minimal distribution of extremal values for the region from the center of the disk cathode to the maximum of the erosion zone and the survival Weibull distribution function (from the maximum to the outer boundary of the sputtering zone). The accuracy of the approximation has been verified for six magnetrons differing in the cathode size or in the design of the magnetic systems. In all cases, good agreement has been observed between the approximation and experimentally measured values. The results reported here can be used to analyze processes that occur on the cathode during sputtering and to refine the calculations of coating profiles. 相似文献
16.
The self-consistent stationary solutions for a planar vacuum diode with a monoenergetic electron beam are fully classified. Formulas are presented to calculate potential distributions of all types and the maximum electric current that can pass through the diode under steady-state conditions at an arbitrary applied voltage. The stability of the solutions is studied. 相似文献
17.
18.
V. I. Gaman 《Russian Physics Journal》1965,8(6):15-18
The transients in a diode for high injection levels are considered. The diode voltage build-up and decay associated with the leading and trailing edges of an applied dc pulse are analyzed. The recombination rate at the nonrectifying contact is assumed infinite. 相似文献
19.
The current of a steady-state electron beam emitted from the magnetically insulated, finite-emissivity edge cathode of a two-electrode coaxial gun is calculated. The dependence of the emission current on the applied voltage is analyzed by solving a self-consistent problem. The field structure near the cathode edge is investigated, and its dependence on the current of the generated electron beam is determined. 相似文献
20.
Current loss without an obvious impedance collapse in the magnetically insulated coaxial diode(MICD) is studied through experiment and particle-in-cell(PIC) simulation when the guiding magnetic field is strong enough. Cathode negative ions are clarified to be the predominant reason for it. Theoretical analysis and simulation both indicate that the velocity of the negative ion reaches up to 1 cm/ns due to the space potential between the anode and cathode gap(A–C gap). Accordingly, instead of the reverse current loss and the parasitic current loss, the negative ion loss appears during the whole pulse.The negative ion current loss is determined by its ionization production rate. It increases with diode voltage increasing. The smaller space charge effect caused by the beam thickening and the weaker radial restriction both promote the negative ion production under a lower magnetic field. Therefore, as the magnetic field increases, the current loss gradually decreases until the beam thickening nearly stops. 相似文献